ABSTRACT
This study aimed to test the photossynthetic performance of the most representative benthonic macroalgae species at the Rodrigo de Freitas Lagoon (Polysiphonia subtilissima, Cladophora vagabunda and Ulva flexuosa subsp. flexuosa) in response to different salinities in order to verify their tolerance limits. Each sample was tested under salinities 10, 15 and 25. Four replicates (light and dark) were used for each salinity. Samples of 10 mg were used for each species, during 30 minutes incubation, under irradiance of 500 ± 5 mmol.m-2·s-1. P. subtilissima and C. vagabunda presented higher photosynthetic production in the salinity of 15 (P < 0.05). U. flexuosa subsp. flexuosa did not differ in its photosynthetic rate under the three salinities sampled (P = 0.09). The present results suggest that future alterations related to the lagoon's salinity may cause alterations in the populations dynamics of the local algae.
Key words:
coastal lagoons; population dynamics; photosynthesis